The present invention relates to the field of digital data transmission. More specifically, the present invention relates to methods and apparatus for maximum utilization of a dynamic varying digital data channel.
One of the challenges of sending data through a dynamically varying digital data channel is how to send a correct amount of data which matches the actual bandwidth of the digital data channel. If the transmitter is sending too much data, data will be dropped during the transmission. If the transmitter is not sending enough data, the channel bandwidth is not fully utilized. There are a number of different protocols currently used to address this issue. TCP is one such commonly used protocol. However, the TCP protocol does not follow the available channel bandwidth very well. In particular, the TCP protocol also under utilizes the channel bandwidth, especially if the latency between the transmitter and receiver is long.
Error correction coding techniques are used to recover data lost during transmission and are based on the principal of encoding and transmitting redundant sets of data such that the receiver can correct errors without the need for retransmission of data. One example of such an error correction technique is forward error correction (FEC). Such error correction techniques require additional bandwidth for the redundant data. Typically, error correction parameters are set to accommodate acceptable loss rates to provide a tradeoff between data quality and bandwidth. For example, with FEC coding, a fixed coding rate is used to provide a target quality for the receiver based on an expected packet loss rate.
The challenges of maximizing bandwidth usage and dealing with data loss are greater when transmitting real-time data over a dynamic varying channel.
It would be advantageous to provide methods and apparatus for maximizing utilization of a dynamic varying digital data channel for sending real-time data, as well as for sending stored data.
The methods and apparatus of the present invention provide the foregoing and other advantages.